An application that acts as an EJB container, enable clients to interact with EnterpriseJavaBeans. Commonly associated with the idea of an ApplicationServer, although EJB is not itself sufficient to provide a WebApplication.
List of open source EJB servers:
Known ones, in alphabetical order, seem to be:
Is VersataLogicServer a EJB? No, the VLS is not an EJB Server, but it can can be hosted on WebSphere. --KyleBrown
How does one go about PickingAnEjbServer?
See EjbLinks